So I've been brewing AG for several years and have never had an issue with basic siphoning from the fermenter to the bottling bucket (I use an auto-siphon). A couple brewings ago, I was having issues drawing air into the auto-siphon and also losing the siphon altogether. I usually use a mesh bag over the end since I dry-hop quite a bit. I thought maybe that was the issue but I still had the problem after removing it. Sooo, I bought a new auto-siphon thinking maybe the seals had worn but on my last two beers, same thing happened and lost nearly 2 gallons on each one. Very confused on this as there are a ton of bubbles when it siphons and at times it completely stops. Fermenter is always on kitchen counter with bottling bucket on floor . I even had to resort to adding water to the hose and tried to start my own siphon today but I couldn't even get that going. Any words of wisdom here?? I'm amazed that this problem is plaguing me and I need to solve it before my next batch.

Have you tried using a smaller ID hose? My autosiphon will leak air at the point where the hose attaches to the siphon tube if it's too big. Usually not enough to lose a siphon but that might be the problem.

I have a large size (1/2 inch) autosiphon. I used to use vinyl tubing and had problems getting a good seal unless I used a smaller size tubing (don't remember if it was 3/8 or 5/16) but getting the tubing on the cane was always a struggle, even with hot water to soften the tubing. Now I use 3/8 ID silicone tubing and no more problems. The tubing slips on easily yet forms a perfect seal and has the advantage that I can boil it to sanitize.

I thought it could be the tubing so I have had a hose clamp on it although I'm using 3/8" tubing. I am noticing the bubbles are coming up from the bottom of the auto-siphon as opposed to starting where the hose is attached so that may eliminate the hose being the issue.

whatsleftofyou - How long is your hose? Mine is 6'. I did replace the hose a bit ago (can't recall if problem started before or after) and it may be a little longer than before. I'll try to shorten and test it.

My 3/8 ID silicone hose is 6 feet long, so I wouldn't think that would be a problem. If the bubbles come from the bottom, it's either sucking air from around the seal or else it's CO2 coming out of solution - I've never had either problem. I just racked a stout last week with my auto-siphon and don't think I saw a single bubble the whole time until I got to the bottom of the carboy. Maybe the CO2 had a chance to come out of solution and reach equilibrium because it had been in secondary for a month and the carboy had sat out at room temperature for a couple of hours before I started racking?